Field of the Invention
The present invention generally relates to cased telescoped ammunition employing a forward control tube, and more particularly to an improved ammunition of this type which prevents premature pressure build-up in the control tube.
As will be appreciated by those skilled in the art, conventional prior art cased telescoped ammunition employs a rear control tube. New proposals have been made to use a forward control tube in a cased telescoped ammunition. While potentially advantageous, applicants' have identified certain problems in the use of a forward control tube for cased telescoped ammunition when used in conjunction with a saddle-type sabot as opposed to a puller-type sabot.
A forward control tube should be perforated to prevent a build-up of an excessive pressure differential across the tube when used in conjunction with a saddle-type sabot as opposed to a puller-type sabot. There is a limit to how thick a tube can be made and still be practically useful. Tubes with a thickness in the practical range would not survive without such perforations. A problem arises because gas from ignited propellant surrounding the control tube passes through these perforations into the control tube before the obturator can move forward to seal off the saddle of the sabot from the control-tube chamber. The front scoop of sabot optimally designed for its primary functions would distort under the pressures generated. Strengthening the front scoop would add parasitic weight to the round and porting the front scoop would result in a loss of pressure across the sabot and resultant loss in available energy for the sub-projectile at the muzzle.